Inconsistent SDK response

Java SDK
2

Simplified test and now it fails on both 4.5 instances:

Observable.range(1, 100, Schedulers.computation())
                .concatMap(i -> bucketProvider.getBucket().async()
                        .counter("test::" + i, 1)
                        .map(doc -> i)
                )
                .toBlocking()
                .subscribe(i -> System.out.println("Successful " + i),
                        throwable -> throwable.printStackTrace());

According to SDK it looks like server is not properly processing Counter requests responding with NOT_FOUND, instead of initializing it.